(CNN) – Former President Jimmy Carter was hospitalized Tuesday in Cleveland, Ohio, for an upset stomach, the Carter Center said in a statement.

He was taken to MetroHealth Hospital, where he was under observation and resting comfortably, the Carter Center said.

“He is resting comfortably and is expected to resume his book tour this week,” it said.

Jackie Mayo, the public information officer for Cleveland Hopkins International Airport, said the 39th president was transferred to the hospital at approximately 11:30 a.m. ET after paramedics met Carter's plane upon its arrival.

Carter is in Ohio to autograph copies of his new book, "White House Diary," at Joseph-Beth Booksellers in the suburb of Lyndhurst.

“We have a lot of secret service here,” an employee of the bookstore told CNN’s Allan Chernoff. “There’s been no official announcement that President Carter is not coming.”